The invention relates to a method and a device for processing mail items to be returned to sender, in accordance with the preamble to the independent claims.
Returning mail items to the sender is necessary if the mail item cannot be delivered to the recipient and cannot be forwarded, for example because the new address is not known or the sender has provided instructions that the mail item be returned to sender if undeliverable.
The detection of a mail item that must be returned to sender is known from prior art. If the recipient is not known at the address provided and a new address is not available, the mail item will be provided by the delivery person with an automatically recognized return stamp. If the mail item contains an instruction, “do not forward, return to sender,” the return stamp is affixed immediately and without first checking a forwarding data file. If a return instruction is recognized during the automatic processing by the OCR reader and if the process of learning the recipient address, including the address interpretation, shows that the recipient is not known under the address provided, then this mail item is placed in the category of mail items to be returned to sender. The same applies if a return stamp is recognized.
The number of mail items to be returned to sender constantly increases and this service by the Post Office helps large-volume customers, for example mail-order houses, to update their address lists.
At first glance, it appears that this problem is easier to solve automatically than the forwarding since the return address is legibly affixed to the mail item and a special search of a data bank is not necessary, as is the case for the forwarding. Practical operations have shown, however, that the OCR reader can clearly recognize sender data with much less frequency, so that a video-coding becomes necessary. The reasons for this are as follows:                1. The localization of sender data on the mail item is above all based on aesthetic aspects, which differ for each sender.        2. Large-volume customers in particular use special logos, specific lettering styles (such as bound handwriting), among other things for advertising purposes as registered trademarks. Automatic OCR readers can clearly identify only a small number of these.        3. Additional data is frequently provided as well, such as a telephone number or a fax number, which leads to non-recognition/rejection by the evaluation algorithms developed for the address recognition.        
In order to achieve the most far-reaching online processing of mail items to be forwarded, including mail items to be returned, German Patent Application 196 44 163 A1 describes a method for the prioritized processing of mail items to be forwarded during the video-coding. However, this prioritized processing cannot be used to solve the above-described problem for the case of large-volume customers where numerous mail items, containing sender addresses that are hard to read by machine, must be returned to sender.